Lost ball ...

Sid and Barney head out for a quick round of golf. Since they are short on time, they decide to play only 9 holes. Sid offers Barney, "let's say we make the time worth the while, at least for one of us, and spot $5 on the lowest score for the day."
Barney agrees and they enjoy a great game. After the 8th hole, Barney is ahead by 1 stroke, but cuts his ball into the rough on the 9th.
"Help me find my ball, you look over there," he says to Sid. After 5 minutes, neither has had any luck, and since a lost ball carries a four-point penalty, Barney pulls a ball from his pocket and tosses it to the ground. "I've found my ball!" he announces triumphantly.
Sid looks at him forlornly, "After all the years we've been friends, you'd cheat me on golf for a measly five bucks?!?"
"What do you mean cheat? I found my ball sitting right here!"
"And a liar, too!!!" Sid says with amazement. "I'll have you know I've been standing on your ball for the last five minutes!"